Nor had there been much light shed on whether the president tried to obstruct the investigation into his campaign.

The report prepared by special counsel Robert Mueller and issued by the Justice Department provided greater detail about those questions. And it offered more information about Russian interference in the 2016 presidential election.

The House will call some of the witnesses mentioned in the report for their full story, not just their cameo appearance in this incomplete report.

For example, the report has the public’s first account from Michael T. Flynn, Trump’s first national security adviser. So, there are a number of contacts mentioned for the first time on the public record between Flynn and Russia that in my reading consistently demonstrate Trump’s partiality to Putin and Russia.

But, until we get a House public hearing with Flynn as a witness, we will not know the full story.

Why did Trump have such a strong bond with Putin? Did Trump have a personal reason, not some foreign policy reason, to favor Russia? Why did Trump push Flynn to be favorable to Russia?

The report does not say.

With Flynn, as with many others, the report is the start, not the finish, of getting the full story.

2. Intelligence committee investigation

Attorney General Barr has announced that a "less redacted" version is, or will be, prepared for a few congressional figures. Presumably he means that the classified parts of the report that describe secret intelligence, which have been redacted, will be shown to the congressional leadership.

But, the leadership cannot itself undertake an investigation.

This is the kind of material that normally goes to the entire House Intelligence Committee. That committee can follow up with demands for documents and closed hearings. And that committee has the trusted expertise to determine that the conclusions of their inquiry can be made public, either via open hearings or by report to the House and the public.

The committee could determine what is actually known by investigators about how Russia viewed Trump and what Russia may have done that secured Trump’s favor.

3. Release grand jury information

Furthermore, the report redacts not just classified information, but grand jury information as well. And Barr may well have omitted, rather than redacted, invaluable grand jury evidence, especially documents.

Barr refused at congressional hearings to seek such an order. But, under sufficient pressure from Congress – against the background of a public that wants the full report and the full story – he could reconsider.

In the Watergate scandal, the prosecutors got exactly such a court order so they could make invaluable evidence available to the House Judiciary Committee.

4. Limit what’s limited by ‘HOM’

There is a great deal of key material redacted in the report with Barr’s label, "HOM" or "Harm to Ongoing Matter." That means the redacted material likely relates to an ongoing investigation by law enforcement.

This appears to have been done with a very broad brush. Under pressure from the House, backed by the public, this could be treated by Barr with a fine scalpel instead.

Yet, Barr’s broad-brush redactions wipe out a whole section on WikiLeaks. Presumably Barr is saying, by this redaction, that the case against WikiLeaks founder Julian Assange is an ongoing matter.

As the recent arrest of Assange makes clear, there is currently an investigation into his actions by the U.S., which has charged him with conspiracy to commit computer intrusion. That means that WikiLeaks’ interaction with the Trump campaign is not the heart of that judicial matter. Rather, the heart is about Assange working with hackers who stole the damaging material.

So the House should be allowed to pursue the part – WikiLeaks and its interactions with the Trump campaign – which is central to the House’s concerns but peripheral to prosecutors of Assange.

5. Documents, documents, documents

Finally, this is just Mueller’s report. Behind it is much more that would be of vital interest to congressional investigators and the public.

The House has every reason to seek and to receive the underlying information.

These various examples are just the beginning of what the House can seek to find as it takes off from the incomplete and redacted Mueller report.

When I was an attorney for the House Iran-contra Committee, we received far more encouragement and cooperation from independent counsel Lawrence Walsh than is promised by Barr. And we went on to dig up striking material during months of hearings.

I believe the House will now pick up where the Department of Justice has left off.

(The writer Charles Tiefer is Professor of law, at the University of Baltimore).